大约有 45,000 项符合查询结果（耗时：0.0380秒） [XML]
Which one will execute faster, if (flag==0) or if (0==flag)?
...is a user-defined type. Then it depends on which overload of operator== is selected. Of course it can seem stupid that they would not be symmetric, but it's certainly allowed, and I have seen other abuses already.
If flag is a built-in, then both should take the same speed.
From the Wikipedia arti...
generate days from date range
...000 days, and could be extended to go as far back or forward as you wish.
select a.Date
from (
select curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a) + (1000 * d.a) ) DAY as Date
from (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all ...
Change MySQL default character set to UTF-8 in my.cnf?
Currently we are using the following commands in PHP to set the character set to UTF-8 in our application.
18 Answers
...
How do I map lists of nested objects with Dapper
... probably work:
Grab the courses:
var courses = cnn.Query<Course>("select * from Courses where Category = 1 Order by CreationDate");
Grab the relevant mapping:
var mappings = cnn.Query<CourseLocation>(
"select * from CourseLocations where CourseId in @Ids",
new {Ids = course...
SQL select join: is it possible to prefix all columns as 'prefix.*'?
... if this is possible in SQL. Say you have two tables A and B, and you do a select on table A and join on table B:
22 Answer...
JOIN queries vs multiple queries
...han several queries? (You run your main query, and then you run many other SELECTs based on the results from your main query)
...
ORDER BY the IN value list
... (introduced in PostgreSQL 8.2) VALUES (), ().
Syntax will be like this:
select c.*
from comments c
join (
values
(1,1),
(3,2),
(2,3),
(4,4)
) as x (id, ordering) on c.id = x.id
order by x.ordering
share...
JSON.NET Error Self referencing loop detected for type
...ceLoopHandling = ReferenceLoopHandling.Ignore,
}, ArrayPool<char>.Shared));
});
}
share
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'IF' in 'SELECT' statement - choose output value based on column values
...
SELECT id,
IF(type = 'P', amount, amount * -1) as amount
FROM report
See http://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html.
Additionally, you could handle when the condition is null. In the case of...
Oracle “(+)” Operator
...dize OUTER joins.
The query would be re-written in ANSI-92 syntax as:
SELECT ...
FROM a
LEFT JOIN b ON b.id = a.id
This link is pretty good at explaining the difference between JOINs.
It should also be noted that even though the (+) works, Oracle recommends not using it:
Oracle re...